(Reuters) – Rescuers in Rio de Janeiro dug desperately in mud and debris on Wednesday to try to find dozens of people missing from floods and landslides that killed at least 133 people in Brazil’s second-biggest city.

The heaviest rains in more than four decades that started on Monday triggered at least 180 mudslides that crushed shacks in hillside slums, causing most of the deaths and leaving 53 people missing.

The city famed for its beaches and Carnival slowly returned to normal on Wednesday after flooding caused transportation chaos on Tuesday, but heavy rain began falling again in the evening and forecasters warned of more to come.

Firemen covered in mud struggled for hours to rescue an 8-year-old boy who had called for help from the rubble of a collapsed house in one hillside slum, only to find that the child had died by the time they reached him.

“I promised his father I would get the boy out alive but I couldn’t,” tearful fireman Luis Carlos dos Santos said.

The mudslide in Rio’s historic Santa Teresa area killed at least 18 people, most of whom had been sleeping on Monday night when the hillside collapsed.

Rescue authorities said a total of 133 people were confirmed dead in Rio state, while 135 were injured and 53 were missing.

Rio Mayor Eduardo Paes urged people living in high-risk areas to stay away from their homes as the city braced for another night of rain.

Authorities say at least 10,000 houses are still at risk of collapse and the national government has sent security forces to help with rescue operations. Paes appealed to the federal government for 370 million reais ($208 million) in aid for emergency operations.

OLYMPIC CONCERNS

Transportation chaos eased on Wednesday but has renewed attention on Rio’s poor infrastructure as it prepares to host the World Cup in 2014 and the Olympic Games in 2016.

The International Olympic Committee said in a statement it planned to have discussions with Rio officials once the situation returns to normal about how the disaster might affect preparations for the games.

“We remain confident that Rio will stage top-quality Games in 2016,” the statement said.

The worst affected area was the city of Niteroi, which sits on the other side of Rio’s Guanabara Bay and where 67 people died, according to the fire service.

In one Niteroi slum, residents desperately searched for survivors in rubble left from 10 houses that collapsed from a mudslide, the Globo network reported.

“I lost my sister-in-law and a niece, and my nephew and brother-in-law are still missing,” nurse Samuel Franca, who managed to rescue his sister from the wreckage the day before, told Globo.

Traffic was moving again in most parts of Rio after nearly grinding to a halt on Tuesday, though Paes urged people to postpone meetings and avoid unnecessary trips. Schools remained shut for a second day.

“From the point of view of mobility, the situation is better than yesterday,” Rio de Janeiro Mayor Eduardo Paes told reporters.

The mayor on Tuesday said 1,200 people had been left homeless and that 10,000 houses remained at risk, mostly in the slums where about a fifth of Rio’s people live, often in precarious shacks that are vulnerable to heavy rains.

In January, at least 76 people died in flooding and mudslides in Brazil’s most populous states of Rio, Sao Paulo and Minas Gerais. Then, dozens of people were killed in a landslide at a beach resort between Rio and the port city of Santos.